Crimping device



Oct. 2, 1956 w. R. EVANS 2,765,019

CRIMFING DEVICE Filed May 2l, 1953 INVENTOR.' l//LL/AM El/AMS BY mld ATTORN s:

2,765,019 Patented Oct. 2, 1956 ice CRMING DEVICE William R. Evans, Oberlin, Pa., assignor to Aircraft- Marine Products, Inc., Harrisburg, Pa., a corporation of New Jersey Application May 21, 1953, Serial No. 356,489

1 Claim. (Cl..153-1) rThis invention is primarily in the field of portable handoperated tools for crimping electrical connectors or terminals onto wire conductors. The invention has particular utility for making connections on existing transmission and feeder lines and the like, where the ends of wires are unavailable or at a distance, for the head of a tool embodying the invention may be quickly fastened around the wire.

For example, in working o nexisting overhead or underground lines there are many places where the conductor is accessible only from one side and the space behind the wire is limited because of nearby structures, so that it is extremely awkward or often impossible to make a satisfactory connection with the tools available today and even where a connection can be made, it is unduly fatiguing to the workman. Moreover, a large portion of such work is on large size wires and cables under service conditions where the connection is required to have a high mechanical strength and a large current-carrying capacity. Thus, during the crimping operation, to insure a high quality connection, the die assemblies must be susceptible to full accurately-aligned closure relatively easily regardless of the limited space around the wire or the angle from which the wire must be approached.

The head of a crimping tool, according to the present invention, can be readily snapped or latched around the Wire, rather than threading the wire through the head of the tool or disassembling and reassembling the tool around the wire. The present invention is described as embodied in a hydraulically-operated hand-tool of a type such as described in the application of Kenneth E. Peterson, Serial No. 167,459, tiled June l0, 1950, now U. S. Patent No. 2,696,850, and that of Herbert C. Stoltz, Serial No. 315,059, tiled October 16, 1952, now U. S. Patent No. 2,722,859, issued November 8, 1955. With a head which can be latched in working position, such a tool can be used in making connections on the standing part of a wire where no ends are available over which to slide the tool head. Moreover, time is saved in making connections near the center of long loose wires, there being no need to thread the wire through the tool head.

An additional advantage of the invention is that it simplifies quick removal of the dies and easy replacement by different sizes or types of dies. Thus, a single tool may be used for several diiferent sizes of wire and for making different types of connections. Moreover, a single tool together with a set of dies is relatively light in weight so that a lineman can carry them up a pole or into a manhole and Work on various sizes of cables and make different connections, all with the one tool and set of dies.

Moreover, with the latch arrangements disclosed, the dies are positively held in accurate relation to each other, and the increase of pressure during the crimping operation serves to lock the tool head more tightly in correct` orientation with respect tothe wire or connector being crimped.

Another advantage is that the die assemblies. are supported so as to require only a small clearance between the portion of the wire on which the work is being performed and any nearby structures, for example, such as the wall of a manhole or a roof truss along which the wire is strung. Thus, in many cases it is unnecessary to pry the wire away from the obstruction or to approach it from an awkward position.

It is an object of the present invention to provide a handy crimping tool capable of producing the high crimping pressures necessary for Work on intermediate and' large size conductors to produce connections having a high mechanical strength and a high electrical performance, and yet one which can be readily used in cramped locations and where only small clearances are available around the conductor being crimped.

The various aspects, objects, and advantages of the present invention will be in part pointed out and in part apparent from the following description taken in conjunction with the accompanying drawings, in which:

Figure l is a side View, partially in section, of a portion of the head of a hand-operated hydraulic crimping tool embodying my invention, and shown unlatched with the dies in the open position;

Figure 2 is a side view, partially in section, of a corresponding portion of the head of a crimping tool embodying a modification of my invention, and shown in the fully latched and crimping position;

Figure 3 is a top View of the tool head shown in Figure 2;

Figure 4 is a side view similar to that shown in Figure 2 of a portion of the head of a tool embodying another modification of my invention and shown in the closed position;

Figure 5 is a side view similar to that shown in Figure 1 of a portion of'the head of a tool embodying still another modification of my invention, shown in the fully open position, with the dies being removed therefrom;

Figure 6 is a side View of the same tool head as shown in Figure 5 showing the action of the latch arm and latch as the head is closed;

Figure 7 is a top view, partially in section, of the head shown in Figures 5 and 6; y

Figure 8 is a View of portions of the latch and arm of the tool head of Figure 5, on enlarged scale, to show in detail the form of the S-curved engaging surfaces thereof; and

Figure 9 is a view of these same portions shown on enlarged scale in engagement.

The type of tool shown in Figure 1 is adapted to make connect-ions of the type formed by telescoping a sleeve or ferrule portion of a connector over a bare portion of a wire, such as the sleeve and w-ire indicated in phantom at 8 and 9, respectively, lin Figure 1 and then crimping the connector into a rm mechanical and electrical bond with the wire. In this crimping operation both the connector and conductor are placed Within the head of the tool, While it is in the unlatched position, the head is latched, and the connection is made by applying a large force to the die pieces, thus crimping the walls of the sleeve inwardly against the conductor, in a manner such as shown in Figure 2, for example, as more fully described in U. S. Patent No. 2,535,013 to Thomas C. Freedom, issued December I9, 1950.

As indicated above, there are many instances wherein it is helpful to be able to latch and unlatch the head of such a tool, for example, in the connection of new feeders to an existing distribution line by using so-called r-tap and X-tap types of connections such as are described in my copending application, Serial No. 299,201, tiled July 16, 1952. These T-tap or X-tap connectors have a generally U-shape which can be hooked onto an intermediate portion of an existing wire and then slid onto a new line from the side and crimped closed to form a I junction.

ln order to facilitate the making of electrical connections without the necessity for threading the wire or connector through the die-assembly-holding portions of the head, generally indicated at 19 in Figure 1, between a tirst die portion or nest die 12 and a second die portion or impression die 14, which is driven by a hydraulicallyoperated ram or piston (not shown), the top of the head has a hinged top portion or arm 16 with an elbow 17 and a side member 19, the top portion being hinged on a pivot bolt 18 so that it may be swung open, as shown. On the opposite free end of the arm 16 is mounted a latch 2S hinged on a pivot 22 and having a hook 24 on its free end. The latch is spring-biased in a counterciockwise direction as seen in Figure 1 so as to catch under a tab or lip 26 on the head when the arm is closed. A bias spring 28 is held in a slot in the latch near the pivot 2f?. and is compressed between a lip 30 on the end of the arm 16 and the bottom ledge 32 of the spring slot. The latch can be manually opened until it abuts against a stop 34, and when released, the spring 2S drives it inwardly against a stop 36, as shown in Figure 1.

The arm 16 is freely hinged on the pivot 18 and hence when the head is elevated, as for example when a lineman on a pole reaches up to hook the arm 16 around the line, it is free to swing down into closed position. The arm 16 is in effect balanced on its pivot 1.8; thus when the head 19 is held in a more or less vertical position, as shown in Figure l, the arm, if fully opened, will remain open. However, when the arm is swung partially closed, its center of gravity passes over the pivot 1S and it continues to swing toward `its closed position. The hook 24 slides down the inclined outer face of the lip 26, past the extremity of the lip, and the bias spring 2i?. pushes the hook 24 into its closed position under the lip 26. The latch stop 36 holds the latch in a position so that thehook 24 can engage this inclined outer surface of lip 26 as the arm 16 is swung toward closed position. v

Thus, the lineman can reach up with the tool and latch it in crimping position onto an overhead line. This overhead latching can be performed with one sweeping motion, saving the time and effort which would otherwise be required for the lineman to climb further up and assemble the tool in crimping position around the wire. In using the tool, the arm 16 is iirst unlatched; then the head of the tool is held downwardly so that the arm swings open, or is manually swung open, and then with an upward swing the tool is quickly latched in place.

Moreover, as described in the copending Peterson application, identified above, this type of hydraulic tool may be provided with a quick take-up piston which is operated from the end of one of the handles (not shown). Thus, as soon as the tool has been latched in place as described above, the quick take-up piston is depressed, causing the dies to close until they take an initial grip or bite on the connector and wire, thus preventing the tool from being accidentally slid sideways away from the desired spot on the connector.

The lip 26 has an overhanging tip which projects slightly downwardly, and has a straight inclined undersurface 38. The under-surface 39 of the hook 24 is straight and correspondingly inclined so that the hook becomes positively engaged behind the overhanging portion of the lip when the impression die 14 begins to drive the connector against the nest die 12.

When the arm 16 is fully latched, a smoothly-ground die-supporting surface 41 on the arm is held in position accurately spaced from an opposing, ground die-supporting surface 43 on a movable die-holder 49.

As the crimping pressure is increased, the hook of the latch becomes more and more lirmly set against the straight under-surface 38 of the lip 26, so that the supporting surface 41 holds the nest die 12 accurately spaced from the die-supporting surface 43 and squarely athwart 4 the straight line path of the impression die 14 as it acts to deform the connector and wire into the nest 12.

In order to allow the hook 24 clearance to engage thc surface B, a recess 4t) below the lip 26 is provided in the head of the tool. The recess is of suflicient depth that the free end of the latch 20 can move down suliiciently far or the hook 24 to clear the extremity of the lip 26. This extra clearance should be equal to twice the amount of the height or rise of either of the inclined undersurfaces 38 or 39 of the lip 26 or hook 24, respectively, alone.

When the arm is swung into its open position as shown in Figure 1, the dies 1-2 and 14 can easily be removed and replaced so Ithat the tool can be adapted for use with various sizes of wires and conductors or for making dif- Iferent types of crimps. The die 12 is supported on the arm `16 by means of a stem 42 held in a socket 43 by means of a ball detent 44 which is biased inwardly toward the socket 43 by means of a bias spring 45 held in a drill hole in the arm by a screw plug 46. iIn order to remove the die 12, it may be pulled out of the socket 43, or if it sticks, it can be tapped out by striking the end of the stem 42 with a light `blow such as with the end of a screw -driver blade, or it can be started out of the socket by prying. The -base corner edge of the nest die 12 is rabbeted at 47 to provide a notch under which the end of a screw-driver blade can be inserted to pry the stem '42 out from the socket 43.

Similarly, the impression die piece 1'4 is held in place within the head of the tool by means of a stem 48 inserted into a die holder 49 which in turn is secured to a hydraulic ram or piston (not shown). A ball detent '52 similar to the detent 414 in the die holder portion of arm 116 snaps within one of the grooves on the stem of the die piece 14 to hold the die in place. A recess 53 in the base of the die piece 1-4 enables the end of a screw driver blade to be inserted for starting the die from its holder in case it is stuck. As explained in the above Peterson application, the pressure of the hydraulic iiuid acting on the ram or piston serves to drive the die holder 49 and die .piece 14 upwardly along a straight path with a tremendous force, guided by the inner walls S0 of the head 10.

It should |be noted that the pivot 18 lies on one side of the center line of this path of the impression die and is spaced laterally therefrom a predetermined distance. The pivot 22, when the arm 16 is in its fully closed position, lies on the opposite side of the center line of the pat-h of the impression die and is spaced approximately the same distance laterally therefrom. Thus, in effect, the nest die |12 is held between these two pivots directly in the path of the impression die 14, and the stress on the two pivots is equal. Moreover, this lateral arrange ment of the pivots allows the tool to be used with a smaller clearance behind the wire being crimped.

With this arrangement, by opening the arm 16, both portions of the die assembly can be quickly removed and a diierent size or style of die quickly and easily inserted.

Another advantage of having the pivots laterally spaced from the path of the impression die is the relatively small amount of unobstructed space required behind the wire in which to insert the arm 16. The only clearance required between -a wire on which work is to be done and an obstructing surface along side of the wire is a space equal to the thickness of the arm 16 plus the height of the die portion of the die 12, there is no requirement for any space for the pivot. Moreover, the wire can be approached with the tool in a head-on direction, i. e. at right angles to the wire and at right angles to the obstructing surface, leaving the operator with the greatest freedom to operate the handles.

In order to provide .a flexibility of use and ease of operation, the head 10 of the tool may be freely rotatably mounted on the body so that it can be twisted at any desired .angl-e with respect to the handles. Apparatus for providing this swivel action while at the same time mainthemselves.

taining the dies in an accurately aligned `relative position is disclosed in the copend-ing application of Herbert C. Stoltz mentioned above. This alignment 'apparatus may be used with vany of the embodiments of my invention herein disclosed.

`In Figure 2 is shown another embodiment of my invention and in this figure, as in the following figures of the drawing, for purposes of clarity of description ele. men-ts of the apparatus performing corresponding functions .are referred to by the same reference numerals followed by an appropriate suffix. In Figure 2, the -form of the under-surface `39a of hook 24a and the under-surface 38a of the lip 26a are rounded so as to have a generally S-shaped meeting line. An advantage of this form of meeting line is that the hook 24a and lip 26a are strengthened by the rounded contours.

This form of S-curved meeting li-ne is disclosed in the application of Herbert C. Stoltz, mentioned above. It is to be noted that with the tool head 21011, when the totp 16a is in its fully latched position, as when a crimping force is beginning to be applied by the impression die 14a the die-supporting surface 41a on the top :16a is accurately spaced from the opposed die-supporting surface 51a on the die holder 49a. Thus, the `amount of crimping, i. e. the amount of impression of the metal of the ferrule "8a and of the wire 9a, is determined by the accurate spacing between these two surfaces when the die-holder 49a has vreach-ed its fully extended position, as shown in Figure 2.

The dies 12a and I'14a are provided lwith means for seating them upon these die-supporting surfaces, for eX- ample, Iby means of die-stems, recesses to receive these stems, and spring-'biased detents to hold them in. When the dies are changed, for example, in a manner as explained in connection with Figure 1, each of the dies of the new set has a predetermined spacing between its back seating surface which rests against one of the tool head die-supporting surfaces 41a or 51a and its front die face. Thus, without the need for making any adjustment of the stroke of the impression die, the proper amount of crimping m-ay -be automatically obtained, regulated hy the spacing of these seating and die face surfaces of the dies The sets of dies are accurately formed to provide the optimum crimping action. The same is true of the Vspacing of the seating and die face surfaces of the dies 12 and '14 and the die-supporting surfaces 41 and 51 of the tool head 10. In this Figure 2, the die `114e is shown in its fully advanced position, driving the connector ferrule Sa and wire 9a into the nest 12a, to form the -connection shown in section.

Figure 3 is a top view of the head of the tool, shown in Figure 2, showing the details of the two pivots. The pivot for the arm 16a is formed by three hinge plates 54, 5S, 56, formed on the head itself, which mate with a corresponding pair of plates 57 on the butt end of the arm and having a hinge bolt 18a passing through all five of these plates. rl`hus, the arm 16a is securely fastened to the head at a position laterally offset from the path of the impression die. It is suiciently strong to resist the large crimping thrust delivered hy the ram. The head and arm are maintained in accurate alignment during crimping by the relatively large number of hinge plates and the length of the hinge bolt 18a. The latch 20a has a pair of hinge plates 58 to provide rigidity and strength, and the width of the pivot 22a is the same as that of the hinge, for it must carry approximately one half of the total crimping force; moreover, the wide hook surface 39a coacts with the lip 26a to serve further to align the die surfaces during crimping.

In Figure 4 is shown another embodiment of my invention in which the hook end S9 of the latch Zibb and the lip 2Gb on the head 10b of the tool are modified, and the clearance required in the recess 6l is reduced. The hook-engaging under-surface 62 of the lip 26h has an arcuate shape of radius Re concentric around the location of the center of the pivot 22b when the arm 16h is in the fully closed position. Also, the lip-engaging under-sur'- face of the hook 59 has the same curvature whereby it mates smoothly with the under-surface 62 of the lip 26b. Likewise, the outer end surface 63 of the latch 2Gb is arcuate in form and concentric around approximately the same center as the hook-engaging surface 62 of the lip 26h. Thus, under the action of the bias spring 281'), the hook end of the latch 20h slides into the recess 6l and holds the dies 12b and 14!) accurately aligned.

An advantage of this arrangement is that no extra clearance is required in the recess 61 for the hook end S9 of the latch 2gb, and, moreover, when the latch has swung under the lip 26b, the arm 16h is prevented from moving. In fact, the outer end 63 of latch 2012 can be provided with a reduction in thickness toward the end of the hook 59, i. e. so that the outer surface 63 is not concentric with the hook-engaging surface 62. This reduction or taper in the hook 59 is obtained by using a radius of curvature Re` for the surface 63, which is longer than the radius Ra, but using a center for Re, which is located further from the center of the top lob than is the center for Ra, as shown in Figure 4. Thus the surface 63 is spaced more widely from the surface 62 at the base of the hook 59 than at its tip; so that as the hook 59 slides into the recess 6l, it tends to jam firmly, and the die 12b is rigidly held in place. Thus, the arm 1611 is prevented from moving on its pivot. lt should be noted that since the engaging surfaces are substantially concentric around the pivot 22h, the nest die 12b is held in exactly the same position during crimping whether the latch 20h is fully closed or not, i. e. regardless of whether any grit should stop the hook 59 short of full entrance into the recess 6l.

In the embodiment of Figure 4, the latch Ztlb remains hooked in spite of the outwardly upturning of the arcuate surface 62, for when the crimping force is delivered by the impression die 14h, the arm lb tends to pivot about its pivot T8Z). That is7 the pivot bolt 22!) is tending to move along the dotted arcuate path of the arrow 64 at a radius Re from the pivot 38h. The force applied to the pivot 22h on the latch 2lb is tangent to this curve 64; in other words, the force on the latch is in the direction of the dotted arrow 66. This force is at an angle of not more than 90 to any portion of the arcuate surface 62, i, e. it points perpendicularly or inwardly with respect thereto, so that there is no component of force tending to open the latch 2% during crimping. Thus, the small bias spring 28h is sufficient to hold the latch in engaged position, in spite of the tremendous force during crimping.

The die-supporting surface 41h on the top 161) is held in an accurately spaced position from the die-supporting surface 5111 on the die holder 49h. The desired degree of crimping may be obtained by the spacing between the die face and seating surfaces of the dies.

During crimping the latch Zlb absorbs about one-hal-f of the total thrust, and the pivot 18h and side portion of the arm 1612 takes the other one-half of the thrust, for these two pivots are approximately equally spaced and on opposite lateral sides of the centerline of the path of the impression die Mb. It should be noted that the undersurface 62 of the lip 26b is located closer to the centerline of the path of the impression die than the surfaces 33, 38a, in Figures l and 2, in order to obtain an inwardlydirected latching component of force, as explained above.

Figures 5, 6, and 7 show a crimping tool in which a latch 76 is pivoted at 73 on the head 79 itself rather than being on the free end of the arm Sti. The hinge comprises three hinge plates 81, 82, and 83 on the head of the tool and a pair of hinge plates 84 on the butt end of the latch 76. The arm is similarly pivoted by means of a pivot bolt 85 passing through three hinge plates 36, 37, and 88 on the opposite side of the head and through a pair of hinge plates 9u on the butt end of a side member 89 of the arm, connected to the main portion of the arm 80 by a elbow 91.

In order to bias the latch 76 inwardly (counterclock- '7 wise) in the direction of the arrow 94 (Figure 6) toward latching position, a pair of small compression springs 96 (see also Figure 7) are set in suitable recesses in the head formed between the hinge plates 81 and 82, 82 and 83, respectively. The butt end of the latch is chamfered at 98 to provide a stop so that the latch cannot be swung open farther than necessary for easy operation. In order to aid the operator in unlatching the latch and swinging it into open position, a thumb tab 10i) is provided on its free end; Figure 5 shows the latch in its fully open position with the bias springs 96 being compressed.

The top Sti is biased outwardly (counterclockwise) in the direction of the arrow 102 towards its open position, that is, toward the position shown in Figure 5 by means of a spring 194 which fits into a recess in the center hinge plate 87. This spring passes around the pivot bolt 35, and is held in proper position by a spacer Washer 168 on the pivot bolt. The ends of the spring are inserted into a hole 119 in the bottom of the recess and a hole 112 in the butt end of the side member 89 of the top S0, respectively.

As seen in Figure 6, the inner side of the latch 76 has an S-curved hook 114 and a recess 116, and the free end of the arm S0 has a correspondingly shaped S-curved hook surface 11S. The latching operation takes place as follows: the latch 76 is released so that the springs 96 push it into the closed (full line) position shown in Figure 6, and then the operator merely swings the arm 80 toward closed position against the torque of the spring 164. As the free end of the arm 8l) (see dotted line position in Figure 6) strikes against the hook portion 114 on the latch 76, the latch is swung partially open to the dotted line position, whereby the end of the arm Sti is enabled to clear the hook 114 and move into the recess 116. The latch 76 immediately swings back to its former position, and when the arm 80 is released, it swings outwardly a short distance to the full line position shown in Figure 6, in which position the two S- curved surfaces 114 and 118 are fully engaged. In this closed and locked position, it is to be noted that the arm 80 is held in fixed position by the side member 89 and by the latch 76 with the nest die 12c squarely across the line of the path of the impression die 14e, and it can not more prior to the application of the crimping force.

In order to unlatch the arm 80, the operator merely presses on the thumb tab lili) to move latch 76 in a clockwise direction about the pivot 78, and the S-curved hook surface 114 cams the free end of the arm 80 inwardly a small distance to free the hook surfaces. Then the arm Sil will automatically swing into the fully open position as shown in Figure 5, under the action of the spring 104.

Among the advantages of this arrangement are those that result from the fact that the arm 89 and its latch 76 are biased so that when the tool head is closed, the hook surfaces are fully engaged and held engaged under spring pressure with the arm 80 in its iinal crimping position. This means that as the crimping force is applied, the S-curved hook surface merely becomes more rmly engaged and there is no additional motion of the nest die 12e. Moreover, following a crimping operation, the operator, who for instance might be working on an overhead line, can release the latch 76 by reaching up with a piece of stilf wire with a hook on the end of it, merely catching the hook over the thumb tab 100 and pulling outwardly to release the arm 3i). The spring 104 causes the arm 3i) to y open, thus fully releasing the connector and wire from the head of the tool.

Another advantage of this arrangement is that the latch 76 is secured to the head of the tool by a hinge structure which is substantially the same as the hinge structure for the side member 89 of the arm 30. Thus, under the tremendous forces developed during the crimping operation, both hinges act the same and hold the nest die 12C in accurate alignment opposite the `impression ldie 14e. The die-supporting surface 123 of the pivoted top portion or arm is a ground surface accurately spaced from the opposing die-supporting surface of the die holder 49C. The amount of crimping obtained with different sets of dies may be regulated by the predetermined spacing of the die face and seating surfaces of the dies themselves.

It will be seen that since the arm 80, when released, is held in the fully open position, it is convenient to remove and replace the dies 12C and 14e, as shown in Figure S. The die 12C is held in a hole 120 in the arm 30 by means of a spring-biased ball detent 122 and rests against the inner die-supporting surface 123 of the arm 80, yand the die piece 14a is held in a fashion similar against the surface 125 by the detent 52e in the recess of the die holder 49C. A pair of transverse recesses 124 may be provided in the die-supporting inner surface 123 of the arm Sti, to provide extra clearance for starting the dies 12C and 14e for removal, if necessary.

In Figures 8 and 9 are shown in detail the forms of the S-curved surfaces 114 and 11S. In order to provide a strong holding action, each of these S-curved surfaces has a central inclined portion 126, which is planar and which is tangent on each side to a circular cylindrical curve, each of which in turn is tangent to the opposed surfaces of the latch and arm when they are in closed position. As shown in Figure 8, one of these curves has a larger radius R1 and the other has a smaller radius R2. In the case of both of the S-curves 114 and 113 on the latch 76 and the arm 80, respectively, the outer curve, i. e. forming the tip or lip, `has the larger radius R1 and the inner curve, i. e. forming the hollow, has the smaller radius R2. Thus, when these two surfaces are engage-d, as shown in Figure 9, the engagement is along the planar surfaces 126, and in each case the tip is clear of its associated hollow. Thus, any grit which may accidentally have become lodged in these hollows is cleared so that it will not affect the accuracy of the position of the arm Sti with respect to the latch 76. This 'accuracy is important, for it assures the correct positioning of the arm Sil with respect to the rest of the head of the tool during crimping and hence the correct positioning of the nest die 12C. Thus, the impression die 14C must always approach thereto the predetermined desired amount to produce an optimum crimping action. It assures that the inner die-supporting surface 123 of the arm 80 is always perpendicular to the path of the impression die 14C. In a particular successful tool head the inclined planar surface was at an angle of 30 and the radius R1 was approximately 1.35 times as large as the radius Rz, being .062 and .046 inch, respectively.

In this arrangement shown in Figures 5-9, the two pivots 78 and 85 are positioned laterally with respect to the center line of the path of the impression die 14e, and they are spaced therefrom an equal distance on opposite sides of it. Also, it should be noted that both of these pivots are positioned away from the inner die-supportmg surface 123 of the arm 80 a significant distance, whereby the impression die 14C as it moves toward its fully eX- tended crimping position, shown in Figure 6, passes to a position between them, the arm and latch being relatively unencumbered and projecting out away from the pivots to an easily accessible position.

Moreover, with this arrangement, the free end of the arm 80 can be easily slipped between an obstruction and the wire to be crimped with no interference from the latch 76. The only space required between an obstruction and the wire is the thickness of the arm 80 and the depth of the nest die 12C. The subjects matter disclosed in conjunction with Figures 5-9 of the drawings are claimed in the copending joint application of Peterson, Neijstrom and myself, Serial No. 418,348, filed March 24, 1954, and assigned to a common assignee with the present application.

It is thus seen that I have provided a tool for crimping connectors and terminals that is Well adapted to attain the ends and objects hereinbefore set forth, and which is subject to a variety of modifications so that it may be best tted for a particular use. It is to be understood that the description and drawings are for the purpose of illustrating the invention in accordance with the statu tory requirements.

I claim:

A tool for crimping conductors having a body, a pair of dies movable toward and away from each other, a rst die holder having a rst die-supporting surface and first means for removably securing one of said dies thereto, a second die holder having a second die-supporting surface movable along a die path toward said first die-supporting surface to a fully extended position and second means for removably securing the other of said dies thereto, a hinge located to one side of said die path and swingably securing said rst die holder to said body, whereby said die holders are enabled to be swung apart to remove said dies, and latch means adapted to hold said rst die holder With said first die-supporting surface in opposed position with respect to said second die-supporting surface and at a predetermined and accurate spacing therefrom when said second die-supporting surface has reached its fully extended position, said latch means comprising a latch, a pivot for said latch on said first die holder on the opposite side of said die path from said hinge, said latch having a hook on its free end, the inner surface of said hook being arcuate and concentric with said pivot, said body having a recess and an adjacent lip on the opposite side of said die path from said hinge, said lip having an arcuate under surface adapted to mate with the inner surface of said hook and also being concentric With said pivot when the first die holder is in the closed position, said hook having an outer end surface which is arcuate and concentric around approximately the same center as said inner surface of said hook, and said body having an abutment near said recess opposite said lip, said abutment having a surface engaging said outer end surface of said hook and being slightly eccentric with respect to said pivot when the rst die holder is in the closed position, the Width of the hook being such that the mating surfaces of the hook and body engage over a substantial area when the latch is engaged, and spring means biasing said latch inwardly toward said die path.

References Cited in the file of this patent UNITED STATES PATENTS 371,805 Vanderman Oct. 18, 1887 1,180,357 Whitney Apr. 25, 1916 1,714,586 Behner May 28, 1929 1,834,697 Giles Dec. 1, 1931 2,113,087 Jensen Apr. 5, 1938 2,133,364 Temple Oct. 18, 1938 2,254,613 Matthysse Sept. 2, 1941 2,422,114 Matter June l0, 1947 

